Sewer-tunnels plan might get streamlined

Friday

Jan 18, 2013 at 12:01 AMJan 18, 2013 at 10:02 AM

The Ohio Environmental Protection Agency is allowing Columbus to delay construction of the second of three huge tunnels while the city looks for ways to make a mandated, 40-year plan to stop sewage overflows a little greener.

Jeb Phillips, The Columbus Dispatch

The Ohio Environmental Protection Agency is allowing Columbus to delay construction of the second of three huge tunnels while the city looks for ways to make a mandated, 40-year plan to stop sewage overflows a little greener.

A total of 18 engineering proposals for pilot projects in Clintonville and the South Side were submitted to the city by last week’s deadline. If those and other projects go well, Columbus could reduce the scale of the two tunnels or eliminate them altogether.

“We’re very excited about it,” said Susan Ashbrook, the assistant director for sustainability at Columbus’ Department of Public Utilities. The city announced plans in 2005 to fix sewer overflows after two settlements with the state. Water from heavy rainstorms seeps into old sanitary sewer lines, overwhelming them and forcing sewage into the Scioto River and other waterways.

Together with sewage-plant upgrades and other work, the tunnels make up the largest public-works project in the city’s history. The city’s $2.5 billion proposal included building three deep tunnels. One, from the Jackson Pike wastewater-treatment plant to near the Arena District, already is under construction. It’s supposed to carry rainwater and sewage.

The two other tunnels designed to carry sewage only — a 14-mile-long one along Alum Creek and an 11-mile-long one along the Olentangy River — could be changed.

Construction on the Alum Creek tunnel was set to begin in 2014. The Olentangy tunnel project would follow. The Ohio EPA is giving the city until 2015 to present a plan for improvements.

The city wants to explore techniques “that mimic natural processes” to deal with rainwater during heavy storms, said Dax Blake, administrator of Columbus’ Division of Sewerage and Drainage. Rain gardens, for example, allow deep root systems to absorb the water. Porous pavement, another possibility, helps with absorption into the soil.

If those and other options deal effectively with the rainwater in Columbus, the scale of the proposed tunnels could be reduced, Blake said. If they don’t, the Ohio EPA will make sure the problem is addressed.

“Both the city and the EPA realize that the Alum Creek relief tunnel may be the best solution,” said Erin Strouse, an agency spokeswoman.

While those pilot projects play out, the city has agreed with the state to accelerate work on the Southerly wastewater-treatment plant, located in the village of Lockbourne in southern Franklin County.

That plant will increase its capacity and implement a high-rate treatment system. Work on such a system was originally scheduled to be finished by 2025. Now, it should be finished in 2019, Strouse said.